Pins of electric plug and socket joints



March 1959 B. L. COOPER ETAL 2,878,339

PI NS OF ELECTRIC PLUG AND SOCKET JOINTS Filed July '7, 1955 United States Patent 2,878,339 PINS OF ELECTRIC PLUG AND SOCKET JOINTS Bruce Lusk Cooper, Portinscale, Lund, Cockermouth, England, Limited, Salford, England near Keswick, and Jack assignors to D. S. Plugs This invention has reference to pins of electric plug and socket joints and has for its object to provide improvements in the construction and mounting of such pins so that they may carry fuses.

It has been proposed to pivot the pins of plug members of plug and socket joints and to secure cartridge fuses in the pins at right angles thereto, so that, when the pin is in its normal position projecting perpendicularly from the plug, the fuse lies in the plug and its end remote from the pin engages a contact whereby the current passes from the pin via the fuse to the contact. With such an arrangement, when a fuse has to be renewed, the pin is swung on its pivot to bring the fuse to a position projecting from the plug whereupon it may easily be detached. This arrangement, while quite satisfactory for many purposes, is not adequate for all and it has certain disadvantages such as the pivoting of the pin itself which is not suitable for a pin of slender construction, as many rectangular sectioned pins used in plug construction are too slight to be pivoted in this way and to have the fuse attached to them.

The present invention provides means whereby the difficulties mentioned may be overcome and whereby pins of any shape, but of very slight construction and straight or inclined at any angle, may be mounted in a plug and have a fuse detachably secured thereto.

According to the present invention a pin for a plug member of an electric plug and socket joint, of the type which has a replaceable fuse associated therewith and is pivoted so as to allow the fuse to be brought into a position wherein it is easily accessible, is characterised in that it is formed integrally with or secured to a bearing member adapted to be pivoted to the plug.

The bearing member may be in the form of a metal block, or where the pin is of slender rectangular crosssection, it may be formed by folding over the end thereof.

The invention will be described further, by way of example, with reference to the accompanying drawings in which pins of various constructions are shown with, for the better understanding of the invention, fuse pins are shown attached though the fuse pins do not constitute part of the invention.

Fig. 1 is an underneath view of cording to the invention, a shown in position;

Fig. 2 is a side elevation corresponding to Fig. 1;

Fig. 3 is an end elevation corresponding to Figs. 1 and 2, and taken from the left hand side of Fig. 2;

Fig. 4 is an underneath view of a modified form of P Figs. 5 and 6 are side elevation and end elevation respectively of the pin of Fig. 4;

Figs. 7, 8 and 9 are similar views of a third practical embodiment of the invention;

Fig. 10 is an underneath view pin of Figs. 7, 8 and 9;

Figs. 11 and 12 are underneath view and side elevaone form of pin acscrew-in cartridge fuse being of a modification of the tion respectively of a pin construction somewhat similar to that of Figs. 4, 5 and 6;

Figs. 13 and I4 are an underneath view and an end elevation respectively of a sixth alternative form of P Figs. 15 and 16 are an elevation of another form of pin;

Figs. 17 and 18 are similar views fication;

Fig. 19 is an underneath view of a form of pin which does not require a peg or pin on which to pivot;

Fig. 20 is a side elevation of the pin of Fig. 19, showing how it is pivoted in a plug; and

Figs. 21 and 22 are an underneath view and a side elevation respectively of yet another embodiment of the invention.

In all the figures similar parts have been indicated by similar reference numerals throughout.

Referring to Figs. 1 to 3, the pin 30 is of metal and is of slender rectangular cross-section having a cranked portion 31 extending from an integral tab 32.

The tab 32 is secured, for example, by brazing to a bearing member in the form of a block of metal 33 approximately cubic in shape, which is bored at 34 to accommodate a pivot peg (not shown) by means to which the pin may be pivoted in the body of a plug. A threaded blind hole is also provided in the bearing member 33 and this serves to receive a threaded end 35 provided on an end cap 36 of a cartridge fuse 37, and the arrangement is such that, when the pin is pivoted in the plug body the second end cap 38 of the cartridge fuse 37 can engage suitable contacts thereon so that current passes from the pin 30 through the fuse 38 to the contacts.

The form illustrated in Figs. 4, 5 and 6 is very similar to that of Figs. 1, 2 and 3, but in this instance the bearing member 33 is round when viewed in elevation, the pin 30 being secured by means of the tab 32 to a flat side of the bearing member.

Referring now to Figs. 7, 8, 9 and 10, the pin 30 is similar to those previously described, being cranked at 31. However, instead of terminating in a tab, the pin end is folded over to form an integral box-like bearing member 39, which is provided with a pivot peg 40 transversely thereof, one of the sides of the bearing member being drilled and tapped to receive the stud of the cartridge fuse 37.

In Fig. 10 a pivot and this serves, plug body.

The form of pin shown in Figs. 11 and 12 is very similar to that illustrated in Figs. 4, 5 and 6, but in this instance the bearing member, again in the form of a circular-sectioned metal block 43, is not permanently secured to the pin 30. Instead, a tab 44 on the pin is formed with a hole whereby it may be clamped to the block 43 by the stud 35 of the cartridge fuse 37. In the form illustrated, the block 43 has an integral pivot peg 45.

The pin and bearing member can, if desired, be machined from a single piece of metal, and such a construction is shown in Figs. 13 and 14 wherein the pin, again denoted by reference numeral 30, is formed as part of and projecting from an extension 46 of a solid metal bearing member 47 having an integral pivot peg 48, the fuse 37 being screwed into the bearing member as before.

The construction of Figs. 15 and 16 obviates the necessity of securing a separate pivot peg to the bearing member, and in the figures it will be seen that the pin 30 is formed by bending one end over through a right angle into an angle sectioned bearing block 49. Opposed pro. jections or lugs 50 serve for pivoting the pin in the plug of a further modipeg 42 is secured into the tab 41 as before, for pivoting the pin to the underneath view and a side body. Thus, the pivot, bearing member and pin 30 a ll formed from one piece of metal.

Figs. 17 and 18 illustrate a pin construction wherein the fuse, instead of screwing into the bearing member, is clipped therein and in this embodiment the end of the pin 30 is cranked at 31 and the cranked portion is folded through two right angles to form a U-shaped bearing member constituted by the side parts 51, 52 and 53. The two side parts 51 and 53 are bored in alignment to accommodate a pivot peg 54 and at the. same time serve to receive and grip resiliently a plain end cap 55 of a cartridge fuse 56. It will be appreciated that a similar method of holding the cartridge fuse in position could be employed with any of the other embodiments of the invention illustrated in the drawings.

In Figs. 19 and 20 is shown a construction wherein the need for a pivot peg,(or lugs such as are shown in Figs. 15 and 16 and which serve the same purpose) is obviated. In this case, the bearing member which is formed integrally with the pin 30 by bending, consists of an extension 57 which is approximately parallel with the axis of the cartridge fuse 37 and which terminates in a bearing tongue 58 which is produced by folding the extension 57 through approximately 120. When the pin is mounted in a-plug body, as is shown diagrammatically at 59 in Fig. 20, a V-groove 60 is provided for the bearing tongue 58, the arrangement permitting the pin 30 to be pivoted through about 80.

The bearing member of the pin illustrated in Figs. 21 and 22 resembles that of the preceding example somewhat, but this embodiment employs a pivot peg 61. The bearing member is shaped as an extension 62 which is folded over to form a hook 63 for the peg 61 which will be located in the plug body in the usual way.

The various constructions described make it possible to provide plug members having very slender current carrying pins of light weight metal incorporating cartridge fuses which are readily replaceable. In the examples described, with the exception of Fig. 10, pin 30 is shown cranked at 31, but it will be evident that the invention may be applied to plugs wherein the pin is at any desired angle. To this end standard bearing members such as 33 and 43 may be provided to which a pin of any shape may be secured as desired to meet any particular design. If desired, the pin may be secured to the lower face of the bearing member 33 or 43 which are in the form of blocks, and if a round pin be needed, this could be attached to the bearing member in a manner similar to the cartridge fuse 37 by screwmg in.

It will be appreciated that alternative constructions may be provided for securing the cartridge fuse 56 to the bearing members. Thus, the bearing members could be recessed to receive the end of a cartridge fuse without a screw, or a spring clip may be provided.

We claim:

1. For an electric plug member having protruding contact pins insertable in electric socket joints, an electrically conductive bearing member adapted to be pivotally supported within the body of a plug member, a cartridge fuse having one end connected by screw attachment to said bearing member in electrical contact therewith, and a contact pin permanently attached to the bearing member with its axis at right angles to that of the fuse; said bearing member being a metallic block having said fuse screwed into one face thereof, and said pin being a flat straight metallic member permanently attached to another face of said block and ofiset laterally therefrom with its outer edge substantially in the transverse plane of the inner end of said block.

2. For an electric plug member having protruding contact pins insertable in electric socket joints, the combination defined in claim 1 in which the longitudinal axis of the fuse perpendicularly intersects the pivotal axis of the bearing member being a virtual extension of its longitudinal axis.

References Cited in the file of this patent UNITED STATES PATENTS 1,288,951 Matthews at al Dec. 24, 1918 1,315,599 Freeman et al Sept. 9, 1919 FOREIGN PATENTS 7,895 Great Britain Apr. 2, 1898 64,777 Switzerland Feb. 22, 1913 92,273 Switzerland Dec. 16, 1921 570,994 France Jan. 24, 1924 

